i965: Check actual tile offsets in Gen4 miptree workaround.

The purpose of the (irb->draw_offset & 4095) != 0 check was to ensure
that we don't have XYy offsets into a tile, since Gen4 hardware doesn't
support that.  However, it's insufficient: there are cases where
draw_offset & 4095 is 0 but we still have a Y-offset.  This leads to an
assertion failure in brw_update_renderbuffer_surface with tile_y != 0.

Instead, simply call intel_renderbuffer_tile_offsets to compute the
actual X/Y offsets and check if either are non-zero.  This makes both
the workaround and the assertion check the same things.

Fixes piglit test fbo-generatemipmap-formats, and should also fix
bugs #34009 and #39487.

NOTE: This is a candidate for stable release branches.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=34009
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=39487
Reviewed-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Chad Versace <chad@chad-versace.us>
Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>

diff --git a/src/mesa/drivers/dri/intel/intel_fbo.c b/src/mesa/drivers/dri/intel/intel_fbo.c
index 35be325..7d6d9f2 100644 (file)
--- a/src/mesa/drivers/dri/intel/intel_fbo.c
+++ b/src/mesa/drivers/dri/intel/intel_fbo.c
@@ -647,6 +647,22 @@ intel_renderbuffer_tile_offsets(struct intel_renderbuffer *irb,
    }
 }
 
+#ifndef I915
+static bool
+need_tile_offset_workaround(struct brw_context *brw,
+                           struct intel_renderbuffer *irb)
+{
+   uint32_t tile_x, tile_y;
+
+   if (brw->has_surface_tile_offset)
+      return false;
+
+   intel_renderbuffer_tile_offsets(irb, &tile_x, &tile_y);
+
+   return tile_x != 0 || tile_y != 0;
+}
+#endif
+
 /**
  * Called by glFramebufferTexture[123]DEXT() (and other places) to
  * prepare for rendering into texture memory.  This might be called
@@ -700,8 +716,7 @@ intel_render_texture(struct gl_context * ctx,
    intel_image->used_as_render_target = GL_TRUE;
 
 #ifndef I915
-   if (!brw_context(ctx)->has_surface_tile_offset &&
-       (irb->draw_offset & 4095) != 0) {
+   if (need_tile_offset_workaround(brw_context(ctx), irb)) {
       /* Original gen4 hardware couldn't draw to a non-tile-aligned
        * destination in a miptree unless you actually setup your
        * renderbuffer as a miptree and used the fragile